Mobility management represents a key and continuing challenge in mobile communication networks, such as cellular communication networks based on Long Term Evolution, LTE, or other Third Generation Partnership Project, 3GPP, standards. As a general proposition, a particular radio node or nodes in a cellular network operate as “serving” nodes with respect to a given mobile node that is active and operating in the network. Serving node updates are often referred to as “handovers”, whereby a mobile node is “handed over” from its current serving node to a newly designated serving node. These updates correspond to movement of the mobile node within the various coverage areas of the network, and, possibly, changing interference conditions, changing cell loads, etc.
In a known approach, the network identifies a neighbor set of radio nodes in relation to the serving node of a mobile node, and monitors reported signal quality or other relevant measurements made by the device with respect to the serving radio node and its neighbors. Depending on the relative signal qualities, the network may initiate a handover of the mobile device from its current serving node to a neighboring node. Handover initiation generally involves signaling to the involved mobile node, as well as signaling between the involved radio nodes.
During handover, the mobile node disconnects from the serving radio node and connects to the new radio node targeted by the handover. As a reflection of their respective roles, the current serving node in the network often is referred to as the “source” node, while the newly designated serving node is labeled as the “target” node. The reconnection process often involves new radio configurations reflecting new or updated resource assignments between the target radio node and the incoming mobile node.
One of the challenges associated with handover processing is that these procedures often take place at or near cell boundaries, where the mobile node may experience reduced signal with respect to either or both the source and target radio nodes. In some respects, however, newer radio technologies and the associated functionality of the networks incorporating them have morphed the handover concept from one in which the mobile node is viewed as moving from one serving cell to another, to one in which the serving “cell” is moved. This notion holds only for corresponding definitions of what is meant by a “cell” and, in this context, a “cell” may be understood as a node-specific radio link or connection used for a particular mobile node, such as may be identified or defined via the use of particular identities. However, it is recognized herein that no effective mechanisms for managing or controlling such “cell” movements have been proposed.
In a non-limiting example, the data connection or transmissions between the network and a mobile node may be scrambled, weighted, coded, or otherwise structured using a DeModulation Reference Signal or “DMRS” that is specifically assigned to the mobile node. Device-specific DMRSs are a type of radio identity that are prominently feature in newer radio technologies, as they provide a basis for serving more mobile nodes or users at the same time, e.g., by using different DMRSs for different users operating in the same cell(s). However, with a finite number of DMRS sequences being available, and in view of the interference problems that arise when the same DMRS sequences are concurrently used within the same coverage area for different data transmissions, it is recognized herein that mobility management becomes, if anything, more challenging with the increasing sophistication of the involved networks and the movement towards device-specific definitions of cells.